strange lighting effect on my curved tunnels

Take a look at this picture first of all...



See the brush above the open section of the tunnel? Why does it have those hard edges on the light map? The tunnel walls and this brush are in the same smoothing group but it gets this weird lighting effect.

Any idea what is causing that? FYI, I can remove all the static_props and it still has the funky lighting so it's not a shadow caused by the models. I'm also fairly certain it's not caused by the opening on the right.

i hope it's not too much trouble but you'll have to delete that one brush and remake it. BTW what's smoothing groups, precious?

I dunno about deleting it and recreating it... it does this all over on my map in the tunnels.

Smooth groups tell the lighting engine that the faces of the brushes should have smooth transistions of light between them. Have you ever seen a 3d model that's flat shaded vs smooth shaded? It makes it look like it's got a lot more geometry to it than it really does....

something like the difference between these two pics:

what's smoothing groups, precious?

Smoothing groups

Honestly, I think that the smoothing groups may be what's messing you up.

In this pic:



Are #1 and #2 smoothed together? If so, they may be taking
precedence over the other faces and giving you that nasty contrast.

Play around with with smoothing groups, and you might end up needing to place a dim light near there to balance everything out.

Smoothing groups are new to hammer 4, and they let you assign groups
for faces to be a part of and those faces should have their lightmaps
smoothed out so as to provide a better illusion of smooth curves.

I've had a lot of trouble with this issue in Echo but as I was pushing
for a deadline I kinda ignored it. Looking at the problem again, I
think I've figured it out (though I'm too lazy to test before I blurt
it out).

For a smoothing group to "blend" two lightmaps together, they most
likely need to share an edge. All up your curved sections this is
probably true, but once you hit the problematic brush I'm guessing that
the bottom face extends past the curved ceiling so its edges are not
touching the edges of the curves. Here is a s**tty picture that might make it a little clearer what I'm trying to say...



I'm guessing that the red dotted line marks your brush. If so, then try clipping that top brush into
sections, so that the visible section of it meets at an edge with the
curved bit.

No idea if that is clear or not, hope I've explained it well enough and I hope it fixes the problem...for your sake and mine :smile:

<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
"For a smoothing group to "blend" two lightmaps together, they most likely need to share an edge."

[/quote]
Yep. :smile:

To be smoothed correctly, faces must meet these restrictions:

• Must share a common edge.
• Lightmaps of the faces must be aligned to one another.
• The lightmap scale must be small enough that at least one lightmap luxel is small enough to fit on each face.
• Must be in the same Smoothing Group.

edit: So, correct me if I'm wrong, but it seems you must assign a new group to every second brush face. Example: bottom left face: smoothing group 1, middle left face: 1 & 2, upper left face: 2 & 3, top middle: 3 & 4, upper right: 4 & 5, etc etc.

If this is correct (and I'm not assuming it is yet, it just seems logical since they must share an edge) then it kinda sucks cause you might only be able to smooth a few things in a map before you run out of smoothing group #'s.

Anyone know? It doesn't say in the documentation.

I'll give it a shot.... If it's not exactly what you've said, it is certainly related... it's the only thing that makes sense.

The way I've built these tunnels is kind of funky too... they're basically square with "curve augmentation".... hehe

something like this (sorry, don't have hammer with me so I can't show a real screenshot) where all the curves are semi-trapezoid shapes...



So where the trapezoid from the left side meets the REAL roof (the blue area) in the larger section of the tunnel, they don't share an edge (not even close, but the edge of the roof would be on the other side of the brush, closer to the wall, while the edge of the trapezoid is right there in the middle of the ceiling brush).

I'll do some clipping tonight and hopefully resolve this... crap there's a lot of these damn tunnels too... hehe

Doh... I just got home... check it out... totally makes sense it doesn't work. Should be easy enough to fix though.

Ugh... I clipped the brush so it shares an edge on all four sides, but still it looks the same... here's a zip with the bsp and two sceenshots in it... if anyone can help, I'd really appreciate it.

http://www.digitalfrag.com/hl2dm/gasworks/smoothtest.zip

Why don't you just bung a light there? That's what I do (along with checking my lightmap scales and texture alignment in the area are the same) :razz:

Some images in this post have been automatically down-sized, click on them to view the full sized versions:

http://www.digitalfrag.com/hl2dm/gasworks/tunnelsfix.jpgI've fixed my tunnels, but it was a big pain in the butt... here's what I WAS doing when it looked like crap:

I created a prefab of sorts (just copy/pasted really) for each section of the tunnels. So I had a "prefab" for a long straight sections, a "prefab" for a 90 degree turn, a "prefab" for the large areas where the big pipes are, etc... I then pieced these together over the length of tunnel to get the whole thing to have the curved top. So, as you saw, that made some funky looking light maps since the faces of all of the tunnel walls did not meet up evenly.

Here's what I did to FIX it: Created a SINGLE "prefab" for a straight section and placed it in the tunnel. I then cloned one and rotated it 90 degrees and place the rest. Then I used the clip tool wherever they met at a 90 degree angle to get them to blend into one another without overlapping.

In addition to this, rather than having these curved pieces line up with the existing square tunnel, I made sure that they extended all the way to the floor. The only reason I have the basic square tunnel that I'm slapping these curved arch peices into is because the curved peieces are all func_detail so they don't seal the level.

Last but not least, previously the two peices that met at the peak of the arch didn't have any thickness to them... what I mean is, the ceiling from the basic square tunnel was immediately above the point at which they connected and this caused a strange ripping effect at the top of the tunnel. So to fix that, I gave myself an extra verticy and made the top peices one unit thick so that the ceiling didn't rip/bleed through. Here's a screenshot of the before and after (obviously the after is also smoother, but that had nothing to do with fixing the strange lightmaps):



Anyway I don't know if that all makes sense to anyone but basically it was due to the faces not lining up properly.

Perfect, that 0 thickness thing at the top of the "bad" tunnel will
almost certainly be what is causing my lighting problems as well.
Thanks for letting us know the solution :smile:

<DIV class=quote>
<DIV class=quotetitle>? quoting ReNo</DIV>
<DIV class=quotetext>Perfect, that 0 thickness thing at the top of the "bad" tunnel will almost certainly be what is causing my lighting problems as well. Thanks for letting us know the solution :smile:
</DIV></DIV>
Glad I could help! I kept thinking that I was typing all of that for nothing... :razz:

ahem... um, So am I correct on how to properly apply smoothing groups, or what?

<DIV class=quote>
<DIV class=quotetitle>? quoting cloudsofthought</DIV>
<DIV class=quotetext>ahem... um, So am I correct on how to properly apply smoothing groups, or what?</DIV></DIV>
Everything you said was correct but it seems there is still more to it. At first I tried just clipping the upper brush so that it met the curved brushes exactly on foor edges but it didn't seem to matter. It was until I made the curved brushes surround the entire area (walls and ceiling) that the problem went away.

Alright, thanks for the reply. Glad you figured it out.